We use many control systems every day, from the kettle that switches off when the water boils to thevideocassette recorder (VCR) we program to record a late night show while we sleep. Thus controltechnology enables devices to be programmed to achieve goals, such as recording the late nightshow, or to respond to events, such as switching off the kettle when the water temperature reaches apre-defined range.

Young children also use simplecontrol systems from the stop and play buttons of a tape recorder tothe mouse and overlay keyboard that produce immediate results on the computer. They progress tocontrolling the movement of a floor robot or turtle using software which allows them to plan and to giveinstructions in the correct sequence to achieve a goal, such as sending the turtle on a shopping trip.

Later on, children make models respond to changes in the environment using software and a controlbox. For example, making a model lighthouse switch on its lamp when the ambient light falls below acertain level, or enabling a buggy they have made (possibly from a construction kit) to navigatethrough a maze.

Clearly, control technology is all around us. It can be used for simple tasks, suchas translating ouractions into something that a system understands, to more complex operations in which the controltechnology varies its behaviour according to external conditions.

systems to be controlled automatically. In the home wemay have a central heating system which lets us wake up to a warm house by turning on the heating ifthe weather is cold. These are often programmable so that we can set them to switch off when we goto work and switch on again before we arrive home.

Some houses have burglar alarm systems that use digital sensors to detect if a window or door isopened, and analogue sensors to detect movement by measuring the amount of infrared radiationemitted by anything warm that moves in the rooms

Burglar alarm systems use software to monitor the state of the sensors and make decisions. Forexample, if the front door opens the software will wait to see if the deactivation code is entered in thecontrol box. Whereas, if the window opens, the system will immediately raise the alarm by switchingon the siren and/or phoning the police.

In the high street we find simple control systems, such as shop doors which open when we approachthem, as well as more intelligent ones

The PUFFIN crossing is a good example of a real system that can be modelled in the classroom. Thepedestrian presses a button to register their intention to cross the road. The control system useskerbside detectors, such as a pressure mat, to cancel this request if the pedestrian walks away,perhaps having crossed the road in a gap in the traffic. It also has infrared sensors to detect people onthe crossing to extend or reduce the ‘all-red’ period to suit the crossing speed of the pedestrian. Thisremoves the need for the ‘flashing green’ stage of the PELICAN crossing.

In industry, computer-controlled robots now handle many repetitive tasks from assembling cars toselecting and grading apples. These autonomous robots use sensors, including cameras, to gatherinformation about their environment, process it and respond appropriately.

In schools

The National Curriculum [http://www.nc.uk.net/] and the QCA Schemes of Work[http://www.standards.dfee.gov.uk/schemes/] provide a framework for pupils’ experience of controltechnology. This experience begins at the foundation stage (pupils aged 3-

to 5-years old). The bookCurriculum Guidance for the Foundation Stage[www.qca.org.uk/ca/foundation/guidance/foundation_stage.pdf], published by QCA, states, forexample, that the practitioner should ‘give opportunities to control a programmable toy, for example afloor robot’ (ibid. page 94).

The following table, published by Becta [http://curriculum.becta.org.uk/docserver.php?docid=806],outlines where control features in the programmes of study for both ICT and D&T in Key Stages 1 to 4,and givesideas for activities to support these.

Know how mechanisms canbe used to make things movein different ways, using arange of equipment includingan ICT control program.

Know how electrical circuits,including those with simpleswitches, can be used toachieve functional results.

Design and make ananimated scene orkineticmodel which receivesinformation from switches;use a control interface todesign and control asequence of events: trafficlights, car park barrier ormodels for fairground rides.

Use control interfaces with acomputer to control systemsthey have designed andmade, eg, for a model theatreor fairground.

14–16

KS4

Apply, in a variety ofcontexts, their existingknowledge andunderstanding of modellingmeasurement and control.

The importance of feedback,and how it can be used toensure the correct functioningof systems.

Design and make computer-controlled systems whichrespond to inputs fromsensors and other systems,eg, a practice simulator forgolf or other games for use atthe school fair, whichrespond when a target isstruck.

Simulations, which can also be considered as control systems, are also an important tool forunderstanding science. For example, during the study of science at Key Stage 2 (Sc2: life processesand living things), pupils have the opportunity to ‘…use simulation software to show changes in thepopulations of micro-organisms in different conditions’ (Sc2, paragraph 5f).

What types of control systems are there?

Control systems can be classified into four types:



Command systems that immediately carry out commands, like a remote control.

Sensing systems that respond to external conditions, like an automatic door.



Conditional systems that vary their behaviour according to external conditions,like acentral heating system.

Command systems blindly do what you tell them. From a control perspective, these systems useoutputs to make things happen but have no other inputs.

Programmable systems, in the narrow sense used above, simply remember the commands they aregiven and blindly execute them in sequence when they are told to start.

Sensing systems have inputs as well as outputs. Inputs allow them to respond to external events, likeheat, light and sound. There are two types of inputs: digital (which return a yes/no value) and analogue(which return a specific value from a range of possibilities).

Conditional systems add a certain amount of ‘intelligence’ to the control system. They use inputs tomonitor external events and some internal logic to make decisions about what outputs to activate(usually referred to as input–

process–

output). This can be seen in the way that the central heatingsystem comes on when a number of time and/or temperature conditions are met. Simple AND ORlogic gates, or software running on a computer or micro-controller (a single chip that contains all themajor elements of a microcomputer), can be used to provide the internal logic for conditional systems.

Real or simulated?

All students should have the experience that comes from designing and building a real system but thatis not to say that simulation is a poor substitute for the real thing.

Simulations are used in industry when designing, analysing and testing systems on both economic andsafety grounds before they are

built.

The Logo computer language, which controls the movement of an on-screen ‘turtle’, is not a poorsubstitute for controling a floor robot, as can be seen from the use of StarLogo[http://education.mit.edu/starlogo/] or NetLogo [http://ccl.northwestern.edu/netlogo/] by Key Stage 3pupils to draw fractals or model populations of termites or study the ecosystem of the rabbit.

Thus, both real and simulated control systems are useful learning tools which should be selected inthe light of the learning objectives.

There are now a number of different software environments where the concepts of control can beexplored in new ways. ToonTalk [http://www.toontalk.com/] and The Magic Forrest[http://www.logo.com/cat/view/magicforest.html] allow Key Stage 1 and 2 children to create games byspecifying how objects on the screen behave and interact. Worldmaker[http://worldmaker.cite.hku.hk/worldmaker/pages], Stagecast [http://www.stagecast.com/] andAgentSheets [http://www.agentsheets.com/] are examples where agent-based simulations can bestudied and created by Key Stage 2 and 3 children.

There are also various software applications that can be used as virtual control systems, for example,Crocodile Technology [http://www.crocodile-clips.com/crocodile/technology/], Logicator[http://www.logicalsoftware.co.uk/], Control Insight [http://www.logo.com/cat/browse/modelling-control.html] and Flowol [http://www.flowol.com/]. Some of these allow you to build systems like trafficlights and burglar alarms, others use on-screen

simulations that are programmed using flow charts oricon-based languages. With the addition of suitable hardware, some of these systems will also controlphysical devices.

Simulations also offer alternative ways of managing the learning. For example, after starting thelesson with a demonstration of a real model, pupils could all use a simulation to develop their controlprogram. As they complete their programs they could then use them to control a real model.

What do you need?

To successfully introduce control technology requires a clear idea of the progression of both the skillsand concepts involved.

A floor robot–

£50–100

(KS1–2)

Pressing buttons on a floor robot to move it forward, backward, and to turn it left or right can be usedas a concrete foundation to sequencing commands and to developing pupils’ ability to predict theoutcome of a simple command sequence.

With the introduction of sensors, the robots can be instructed to respond to changes in theenvironment, such as light or sound levels

Logo

–

£0–100

(KS1–4)

By progressing to software like Logo, which can display a history of commands, repeated sequencescan be identified and the repeat command introduced. This leads to refining sequences of commandsby editing, and to being able to experiment with questions like “What do we change to make it draw asquare/rectangle/triangle?”

Introducing procedures or functions as named blocks of code allows for the use of variables togeneralise a procedure, and recursion to get a procedure to call itself.

A

control interface–

£60–260

(KS1–4)

A control interface allows computer programs to control a range of models and respond to externalconditions. There is an equivalent progression when using a control interface but the conceptsintroduced depend on the software being used.

Control software–

£0–100

(KS1–4)

Most control interfaces include software to program the device from a computer, but this is not the onlyoption. Some software packages work with a range of hardware devices. These can be used toprovide additional facilities not present in the software bundled with the interface, or to standardise thesoftware used to program a range of different devices.

The software used to control devices can be classified as textual, flowchart or iconic. Textual software,like Logo, requires the user to type in text such as loop [if sensorA > 128 [ab onFor 20] which switchesmotors a and b on for 20 milliseconds when sensor A records above a certain value.

In flowchart based software, such as Flowol or Logicator youwould draw a diagram. (For examples,see the Flowol [http://www.flowol.com/] and Logicator [http://www.logicalsoftware.co.uk/] websites).

In iconic software, such as Lego RoboLab and Junior Control Insight, icons representing the sensor,the motors and a 2

second delay are placed in the appropriate order. (For information about RoboLabBecta

in use, see the Kent NGfL Robolab Project website [http://www.west-borough.kent.sch.uk/robolabeval.htm] and for examples of Junior Control Insight, see the Logotronwebsite [http://www.logo.com/cat/view/junior-control-insight.html].

Iconic languages and other metaphors have been used to make programming more accessible toyoung children–

see the Playground Project [http://www.ioe.ac.uk/playground/].

Models and sensors–

£40–200

(KS1–4)

Starting with the on, off and wait commands, a sequence of instructions to control a flashing lamp in amodel lighthouse can be created.

By using traffic lights to model a pedestrian crossing, the concept of a programmed sequence that istriggered by a sensor (the button pushed by the waiting pedestrian) can be introduced. This conceptcan be developed into systems that vary the timings dependant on infrared sensors that monitor trafficflow and pedestrian movement. This leads on to a consideration of feedback in control systems (see[www.roads.dft.gov.uk/roadnetwork/ditm/tal/signs/01_02/] for the details of a Puffin crossing)

It is useful to start with pre-built models so that the initial focus can be on the concepts of control thatare being introduced. Pupils can then progress to building models–

initially from kits–

but as this istime consuming it is best considered as a separate activity.

Electronics and construction kits–

£5–300

(KS2–4)

There are a number of products designed to support work in this area. Products range from thoseused to deliver a broad range of curriculum, such as RoboLab, to those designed to be a consumablecomponent (£5) which enable pupils to build a significant element of control into the products whichthey designand make.

The Technology Enhancement Programme (TEP) has designed a number of consumablecomponents including the IQ micro-controller[http://www.marconiect.org/php/display.php?module_id=99&item_id=803], and the Picaxe micro-controller system which is programmed from the computer. The Picaxe software uses flow charts anda text-based language, and the license enables pupils to use the software at home.[http://www.mutr.co.uk/Prog/Prog_picaxe.htm]

The BBC’s Build-A-Bot Kit [http://www.bbc.co.uk/science/robots/techlab/robot_order_info.shtml],designed by TEP, has on-line support materials [http://www.bbc.co.uk/science/robots/teachers/]detailing how the relevant parts of the curriculum can be delivered using this resource for pupils aged7-

to 16-years old.

RoboLab starter kits, from the Lego Mindstorms for Schools range, contain all the parts necessary tobuild and control a number of different models. Hertfordshire LEA publishes materials detailing howthe QCA units for Years 5 and 6 can be delivered using this resource. Hertfordshire schools candownload these resources from[http://www.thegrid.org.uk/learning/ict/primary/ict/control_and_monitoring/index.html], other schoolscan purchase the materials from Commotion as Product code: 07954-1 (£24.95).

There are also a range of resources designed to support annual competitions such as Micromouse[http://www.mmu.ac.uk/micromouse/schools.shtml] and Technogames[http://www.bbc.co.uk/science/robots/techgameentry/index.shtml]. Resources include:



Swallow line-follower

robot [http://www.swallow.co.uk/dash/dash1.htm]



wall-follower robot [http://www.swallow.co.uk/mad/follower.htm]



various TEP components sold by Middlesex University[http://www.mutr.co.uk/Prog/Prog.htm].

If you have Texas instruments graphing calculators then Norland Research produces a PIC basedcalculator-controlled robot kit [http://www.smallrobot.com/scimath.html] which has two motors and twopressure switch inputs.

What issues should I consider before buying?

General considerations

In a primary school,

a combined control interface and datalogging box that is able to fulfil both sets ofcurriculum requirements may offer significant benefits. For example, training is simplified andconfidence in using the system transfers between the different activities.

Some devices use onesoftware application to run both the control and datalogging functions, while others use separatesoftware applications for each function. This may simplify its use but you need to consider if thefunctionality of either component has

been compromised. Can the combined solution deliver all yourplanned control and datalogging activities?

If you already have some control interfaces and need some more you should consider the benefits ofstandardising at least within a year group or key stage. This reduces the training requirement andallows development of common curriculum support materials. To achieve this would mean eitherbuying more of the same hardware or choosing hardware that can use a software package compatiblewith the old equipment.

Other issues to consider:



Are teaching resources available for the product over the internet? For example, from yourLEA, Regional Broadband Consortium (RBC), or from the supplier.



Is training and support for the product available locally?



Are thereany support networks for the product, such as other local schools or internetcommunities?



Does your LEA or local Science, Engineering and Technology Point (SETPOINT) supportthe product?

(SETPOINTS have been established by SETNET, the Science EngineeringTechnology MathematicsNetwork. SETNET is one of the outcomes of a government initiative: Action for Engineering.SETPOINTS operate as a focus for teachers, business and industry to obtain information aboutresources, schemes and initiatives concerned with

science, engineering, technology and mathematics.Many SETPOINTS offer taught modules for 30 pupils, including transport to and from the school, forless than £5 per person. This is an interesting way to introduce control; if you plan to take advantageof this scheme then the equipment used by the SETPOINT should be considered. To find your localSETPOINT, visit the SETNET website [www.setnet.org.uk/] or telephone SETNET on 020 7636 7705.)

Considerations when purchasing floor robots



Is it accurate? Some cheaper programmable toys are not very accurate, particularly whenturning, and this can have an impact when pupils are trying to predict the outcome of asequence of commands.



Does the robot require a computer? Having a set of buttons to press on the robot

allowsyounger children to access the activity.



Can it connect to the computer? If it can, then you need to ensure that your computermeets the system requirements stated by the robot’s manufacturer. This may includehaving a free serial, parallel or universal serial bus (USB) port.



Can it be programmed from the computer? Some floor robots can be programmed via acable or infrared link to a computer. This opens up more possibilities for progression to, forexample, Logo.



Does it or can it have sensors attached? Having sensors would allow for progression tomore complex control programs.

What batteries can it use? The cost of disposable batteries must be balanced against theneed for charging rechargeable batteries in time for the lesson. Some devices offerbothoptions.

Considerations when purchasing Logo or turtle graphics

Logo can be used from foundation to post graduate level, so selecting an appropriate implementationis essential. The Massachusetts Institute of Technology (MIT), where Papert’s team first created Logoin 1967, hosts an authoritative website which includes information about different implementations ofLogo [http://el.media.mit.edu/logo-foundation/], free downloads, news, history, latest research andpublications. Many of the simplest Logo-based programs implement a small subset of the languageknown as ‘turtle graphics’. Unfortunately these simple implementations are not featured on the MITwebsite. An alternative listing, including the subsets of Logo, can be found by searching Curriculum

Online [http://www.curriculumonline.gov.uk/].

Questions to ask:

Does it have multiple levels for progression? Some versions of Logo vary the user interface in anumber of steps from the simplest presentation of four icons or command buttons (similar to thebuttons on a floor robot) to full text entry.



Can the keyboard’s arrow keys be used to move the turtle? This allows children atfoundation level to successfully complete simulation exercises, like parking a car or movinga bee from flower to flower, whilst learning that pressing right turns a quarter turn ratherthan moving to the right.



Can you load backgrounds and change turtles easily? This allows activities, such as thetwo mentioned above, to be prepared in advance and then simply loaded.



Can it control external devices, such as a robot?



Can it handle sound, video, web pages and animation?



Can you create interface objects like buttons, sliders, monitors, switches, and text boxes?With more advanced versions of Logo you can make user interface objectsinteract withthe program you have written. For example, buttons can invoke procedures and sliders canchange the value of variables.

Considerations when purchasing a control interface

The first consideration should be how does the interface connect to the

computer? Some, like TEP’sIQ micro-controller and Data Harvest’s Learn & Go [http://www.data-harvest.co.uk/control/learn_go.html], do not need to connect to a computer as they have on-boardprogramming However, most control interfaces require a computerconnection and this placesconstraints on which computers can be used.

A system that can be programmed from the computer will have a component that plugs into thecomputer. This is true even if the control interface is wireless, as a transceiver will needto be pluggedinto the computer to enable the wireless communication.

The connection to the computer can be through serial, USB, or parallel ports. Traditionally theconnection was via the serial port, but modern computers tend to use the faster USB port.Consequently, you will need to audit the computers that you intend to use with the interface anddetermine how port availability will constrain your selection. Most interfaces have one or other type ofport rather than both. Some may be able to use a USB to serial converter/adapter. There may besome constraints imposed by using an adapter, which may appear as an unusual port name such asCOM9 which the control software may not allow.

If the preferred control interface is supplied with a USB connection, your computer audit must alsoinclude an audit of installed operating systems. This is because two versions of Microsoft Windows doBecta

How many outputs are suitable for controlling motors? Don’t assume that all outputs cancontrol motors as more current is required and additional functionality may be needed,such as the ability to change the speed and direction of the motor.



How many digital and analogue inputs are there? The number required depends on theactivity. For example, a robot with a touch sensor on the front and rear bumpers and a lightsensor on the roof would require three inputs, two digital ones for the switches and oneanalogue one for the light sensor. (The speed and resolution of the analogue to digitalconverters is less likely to be limiting when the analogue ports are being used as controlsensors rather than data streams and thisis why some devices that combine control anddatalogging functionality are compromised.)



Can existing electrical equipment, which commonly uses 4mm plugs, be connected? Thisallows the integration of computer control with other electrical circuit buildingactivities.



Can programs be downloaded, stored and run in the interface so that it can be used awayfrom the computer? When combined with the ability to run multiple copies of the softwarewithout the interface connected, this allows several groups of children to create programsat the same time. When their program is complete the interface can be connected to thecomputer to download the program.



What is the power source? Using batteries for a control interface allows for the portabilitydescribed above and bypasses the requirement for an additional power socket. However,the cost of using disposable batteries can be significant and using rechargeable batteriesadds the risk of flat batteries disrupting the lesson. If mains power is chosen, then ensurethat

you have enough power sockets for the equipment in use.



Is the power to the interface isolated from the computer? Without isolation there is a smallchance that power from the interface can damage the computer.

Considerations re control software

Selecting

software to teach control is similar to selecting other software. You need to ensurecompatibility with your computer’s operating system and the control interface, and then assess ease ofuse and functionality.



What style of programming does it use?



Is it

compatible with all your control interface hardware?

Considerations re sensors



What sensors are available? A simple switch, which is digital, will indicate when a robot istouching an object and simulate a pelican-crossing request, but more complex controlrequires analogue sensors.



Can you build your own? If you are limited to the sensors provided by the manufacturer,then ensure that all the sensors you require are available for the interface you select.



Are they suitable for the intended environment? The system you want to build may havespecific requirements for robust sensors working in a particular range.

Considerations re models

Models can be designed and built by the pupils, bought as kits or pre-built ready for use. As mentionedpreviously, designing and building models is time consuming and is best considered as a separateactivity. When introducing control, it will be easier to pre-build the models.

Is progression possible without rebuilding models? (If so, this will help to keep the focus ontheconcepts of control being introduced.)



Are they robust? Some of the models built from construction kits can come apart duringuse. If you are using building blocks to create models you may want to try using PVA(polyvinyl acetate) adhesive to temporarily fix non-moving parts together. (Blocks gluedwith PVA can subsequently be separated by soaking them in water.)

What are the implementation issues?

Plan time to familiarise yourself with the various components and how they connect together. Withanything that connects to a computer, ensure that the software is installed on the computer you will beusing in the lesson. Models may need to be built and stored or components for each model placed inseparate boxes. This simplifies the assembly and keeps the focuson the control aspect rather than,for example, the colour of the bricks used to make the model.

Check that power is available. Depending on the equipment, you will either need a free mains socket,batteries that have been charged, or spare disposable batteries.

Other sources of information

Curriculum related

Curriculum Online is a single point of reference for teachers to find, compare, select and sharerelevant digital resources including software and materials for control technology.

[http://www.curriculumonline.gov.uk/]

Using ICT to meet teaching objectives in secondary design and technology (Word document)

Research at MIT, which gave rise to Logo and Lego Mindstorms, continues to produce interestingdevelopments. The Cricket is a tiny computer that can control two motors and receive information fromtwo sensors. It is powered by and is about the same size as a 9-volt battery[http://handyboard.com/cricket/]

Crickets are available from Gleason Research

[http://www.gleasonresearch.com/index.html]

More about Crickets:

Media Lab at MIT

[http://lcs.www.media.mit.edu/people/fredm/projects/cricket/]

IBM Systems Journal (PDF)

[http://www.research.ibm.com/journal/sj/393/part2/martin.pdf]

To Mindstorms and Beyond: Evolution of a Construction Kit for Magical Machines–